Vibratory work machines such as, for example, vibratory compactors are well known. Typically, vibratory work machines such as compactors for soil, gravel, asphalt, etc. include vibratory mechanisms that are configured to provide one or more frequency settings as well as one or more amplitude settings. In operation, the vibration amplitude and vibration frequency of a vibratory compactor may be varied by a user to suit a particular application. For example, the vibration amplitude and frequency suitable for compacting gravel for a road may be different from the vibration amplitude and frequency suitable for compacting soil for a footpath.
Typically, vibratory compactors include vibratory mechanisms that produce vibrations using two or more weights that rotate about a common axis. The weights are eccentrically positioned with respect to the common axis and are typically movable with respect to each other about the common axis to produce varying degrees of imbalance during rotation of the weights. As is commonly known, the amplitude of the vibrations produced by such an arrangement of eccentric rotating weights may be varied by positioning the eccentric weights with respect to each other about their common axis to vary the average distribution of mass (i.e., the centroid) with respect to the axis of rotation of the weights. As is generally understood, vibration amplitude in such a system increases as the centroid moves away from the axis of rotation of the weights and decreases toward zero as the centroid moves toward the axis of rotation. It is also well known that varying the rotational speed of the weights about their common axis may change the frequency of the vibrations produced by such an arrangement of rotating eccentric weights.
Known vibratory mechanisms, such as that disclosed by U.S. Pat. No. 3,656,419 to Boone, typically enable users to select a desired vibration frequency from one or more possible frequencies independent of the selection of a desired vibration amplitude. In some cases, the vibratory mechanism may enable a user to adjust only vibration amplitude while vibration frequency remains fixed or uncontrolled, or may enable the user to adjust only vibration frequency while vibration amplitude remains fixed or uncontrolled. Unfortunately, these known vibratory mechanisms do not establish any relationship or dependency between vibration frequency and vibration amplitude. As a result, a user may be permitted to inadvertently select a vibration frequency and amplitude combination that results in a decoupling between a vibratory mechanism and a surface being compacted by the vibratory mechanism. Further, some vibratory mechanisms may permit the user to select an operating condition in which the vibratory mechanism vibrates at a high frequency and a high amplitude, which may result in a vibratory overload (e.g., a bearing overload) within the vibratory mechanism and/or a device, machine, etc. to which the vibratory mechanism is operatively coupled. Still further, some vibratory mechanisms permit users to select one or more vibration frequencies that are coincident with natural resonant frequencies of the vibratory mechanism and/or a device, machine, etc. to which the vibratory mechanism is coupled.
The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.